Coating for molds and cores.



.rived from hard washed coke of a UNITED SATES JOSEPH EMILEGERNELLE-DANLOY, OF MOU'LIN S,

PATENT OFFIC.

FRANCE.

COATING FOR MOLDS AND 'CORES.

No Drawing.

France, have invented certain new and useful Improvements in Coatingsfor Molds and Cores, of which the following is a specification.

The present invention relates to a product destined to replace blacklead and other products usually employed to coat molds and cores madeout of sand, which are intended to be dried or baked before casting.

This product can be employed for castings of steel, cast-iron, copper,bronze, aluminum and all metals'in general. My improved product iscomposed of coke dust, wood charcoal, pipe clay, and starch, the latterpartly in the form of powdered raw starch and partly in the form of adried starch paste. 3

Under the term cokedust I desire to be understood quality suitablefor'metallurgical operations and ground to a fine powder. Theingredients named form a com osition which when mixed with water to cm apaste capable of being applied to the mold or core by means of a brush,produces a-' thin but hard and smooth coating which does not detractfrom the quality and appearance of the cast metal, prevents the adherence thereto of sand from the mold or core. so that the castings 410not need any subsequent cleaning, and enables castings to be obtainedwhich are free from surface cracks and blemishes.

The resistant and coke dust and fire clay are already known inconnection with coatings for molds and cores and flour has also beenemployed .therewith in compositions for the same urpose. Thesecompositions have hitherto een v used without any specialagglutinativeadditions, or in someinstances sour beer has been proposed as anagglutinative. however found that the addition I have of driedSpecification of Letters Patent.

the impalpable powder 'debroken out of the sand is protective qualitiesof Patented Mar. 6, 1917.

Application filed December 10, 1914. Serial No. 876,479.

which is in eflect dextrin and flour paste,

water (whereas flour. itself is is soluble in not fully soluble and onlyvery slightly agglutinative) provides a perfect agglutinative andproduces in combination with the other ingredients mentioned acomposition the employment of which gives greatly improved results. Theforegomg materials are em ployedin the new product in the following. f

proportions Coke, washed 40 Charcoal .1 32.5% Pipe-clay 22.5% Starchpaste, dry 2 Starch, raw, inpowder 3 These quantities. may vary slightlyac cording to the quality of the materials employed. These arepulverized together and very finely bolted, giving an impalpable and.

very homogeneous powder of a blackish shade.

This product is employed mixed with an equal volume of water, and isapplied tothe surface by means of a brush and when dried appears like anenamel varnish. The taking I made without necessitating other work thanthe ordinary removal of the mold, obviating the rasping of the piecesafter the casting. The castings obtained have a very smooth surface andthe metals keep their qualitiesfand their natural shade; the castingsarevery-clean and do not soil when they are touched as do those obtainedwith the use of black lead or all other similar materials, which has acertain importance when the pieces, have to be finished.

Moreover, the weight of the newproduct is 40% less. than that of anequal quantity of black lead of good quality, which permits of a greateconomy from its use.

Having thus described my invention and the manner to work it out, Iclaim patent for: r v

1. A composition for use in coating sand molds and cores, comprising incombination coke dust, charcoal, pipe clay and raw 2. A compos't1on foruse in coating sand molds and cores comprising known carbonaceousmixtures previously employed for this purpose together with anagglutinant consisting of dry starch paste.

In witness whereof I have signed this specification in the presence oftwo wit- 10 nesses.

mum EMILE GERNELtE-MNLW.

Witnesses: I

JEAN 4 GnRMAm, Louis GomoHoN.

